WEEK 2 Flashcards by Nerisse Rogador

What are the characteristics of hydrogen?

Can be polar or non-polar depending on which atom hydrogen is bonded to
Involved in dehydration and hydrolysis reactions
Found in almost all organic molecules

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What are the characteristics of Hydroxyl (OH) groups?

Polar
Involved in dehydration and hydrolysis reactions
Found in carbohydrates, nucleic acids, alcohols, some acids and steroids

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What are the characteristics of Carboxylic acids (COOH)?

Acidic
Involved in peptide bonds
Found in amino acids and fatty acids

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What are the characteristics of Amino (NH2)?

Basic
May bond to an additional H+ becoming positively charged (NH3+)
Involved in peptide bonds
Found in amino acids and nucleic acids

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What are the characteristics of Phosphate groups (H2PO4)?

Acidic
Link nucleotides in nucleic acid
Energy carrier group in ATP
Found in nucleic acids and phospholipids

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What are the characteristics of METHYL (CH3)?

Non-polar
Tends to make molecules hydrophobic
Found in many organic molecules especially common in lipids

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What is Oxidation?

Oxidation is the loss of electrons/loss of hydrogen atoms and is also the gain of oxygen/OH group

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What is Reduction?

Reduction is the gain of electrons/gain of hydrogen atoms and is also the loss of oxygen

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What are the major anionic (-ve) groups in the body?

Carboxylate groups
Phosphate groups
Sulfate groups

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Compounds that contain nitrogen are usually _______ and can acquire a -ve charge

Basic

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Simple sugars form _________ in condensation reactions

Polysaccharides

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Nucleotides form ________ in condensation reactions

Nucleic acids

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Amino acids form __________ in condensation reactions

Proteins

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Fatty acids & Glycerol form _________ in condensation reactions

Lipids

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Define ‘monosaccharides’ and give the equation formula used to calculate

Monosaccharides are carbohydrates that cannot be hydrolysed into simpler carbohydrates

Cn(H2O)n

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What is a disaccharide and its general formula?

Condensation products of two monosaccharide units

Cn(H2O)n-1

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What is an Oligosaccharide?

Condensation products of two to ten monosaccharide units

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What is a Polysaccharide?

condensation products of more than ten monosaccharide units that are long carbohydrate molecules of repeated monomer units joined together by glycosidic bonds

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What is a glycosidic bond?

a type of covalent bond that joins a carbohydrate molecule to another group. During this bond formation water is formed and thus is called condensation.

(Subunits of disaccharides and polysaccharides are linked by glycosidic bonds)

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What is the difference between Homopolysaccharides and Heteropolysaccharides?

Homopolysaccharides are formed by one type of monosaccharide whereas Heteropolysaccharides are formed by more than one type

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Glycogen is the storage of homopolysaccharide in animals and fungi, what are the other properties of glycogen?

More highly branched than amylopectin
Converted to glucose in a hydrolysis reaction
Mainly stores in the muscles and liver cells in mammals

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Most lipids are ________ formed by condensation reactions of alcohols and fatty acids

Esters

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What is the solubility of lipids in solvents?

Lipids are insoluble in water but soluble in organic solvents such as chloroform, alcohol and acetone

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What does a lipid molecule consist of?

1 molecule of Glycerol and 1-3 molecules of fatty acids

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What does a fatty acid consist of?

Carboxylic acid with hydrocarbon side chains

What do fatty acids exist in the body as?

Free acids & Fatty acyl esters

Fatty acids are released from these lipids on hydrolysis by ________

Lipases

What can fatty acids be divided into?

Saturated fatty acids and Unsaturated fatty acids

What is the difference between unsaturated fatty acids and saturated fatty acids?

Unsaturated fatty acids contain double bonds with general formula (CnH2n-1 COOH) whereas Saturated fatty acids do not contain double bonds with general formula (CnH2n+1 COOH)

What is the difference between monounsaturated fatty acid and polyunsaturated fatty acid?

Monounsaturated fatty acids contain ONE double bond whereas Polyunsaturated fatty acids contain more than one double bond

Define 'Essential fatty acids' (EFA)

Fatty acids that cannot be synthesised by the body and therefore should be supplied in the diet

What is a triglyceride?

Simple lipids in which glycerol backbone is esterified with three fatty acids

What is esterification?

The process of combining an organic acid (RCOOH) with an alcohol (ROH) to form an ester (RCOOR) and water

If three hydroxyl groups are esterified with the same type of fatty acid then the lipid is a _______________

Simple Glyceride

If three hydroxyl groups are esterified with a different type of fatty acid then the lipid is a _______________

Mixed Glyceride

If three hydroxyl groups are esterified with DIFFERENT types of fatty acids then the lipid is a ________________

Mixed Glyceride

What are phosphoglycerides?

Membrane lipids in which two fatty acids are attached in ester linkage to the first and second carbons of glycerol and a highly polar or charged group is attached through a phosphodiester linkage to the third carbon

What are the characteristics of phospholipids?

- Amphipathic (contains large polar and non-polar regions) - Phospholipid has a polar hydrophilic "head" with a phosphate group attached to glycerol and a positively charged base and a non-polar hydrophobic "tail" with two long fatty acids - Amphipathic nature arranges it to a bilayer

Phosphatidycholine (Lecithin) is found in membranes, what makes it a polar molecule at neutral pH?

Amine is +ve at neutral pH and Phosphate is -ve

What are the two isomers of Glucose called and how are they determined?

"D-Glucose" (also known as dextrose) and "L-Glucose" The OH group on the chiral carbon farthest from the carbonyl group determines if it is an L or D isomer. L is for rotating optical light to the LEFT and D is for rotating optical light to the RIGHT.

Carbohydrates are aldehydes or ketone derivatives of ____________________

Polyhedric Alcohols

List the differences between macromolecules and micromolecules

- SIZE (micro SMALL and macro LARGE) - WEIGHT (micro LOW MOLECULAR WEIGHT and macro HIGH MOLECULAR WEIGHT) - STRUCTURE (micro simple and macro complex) - SOLUBILITY IN INTRACELLULAR FLUID (micro HIGHLY SOLUBLE and macro INSOLUBLE

If the carbonyl group is an aldehyde, the sugar is an ____________

Aldose

If the carbonyl group is a ketone, the sugar is a ___________

Ketose

What are the functions of polysaccharides?

- Storage (Starch, Glycogen, Insulin) - Structure (Cellulose, Chitin)

Describe the structure of Glycogen

Glycogen contains chains of 12-14 alpha D-Glucose residues with branching by means of glycosidic bonds

What are the main conjugated/compound lipids found in the body?

Phospholipids Glycolipids Lipoproteins

What is the chemical name for essential fatty acids (EFAs)?

Polyunsaturated fatty acids (PUFA)

Name three Essential Fatty Acids (EFAs)

Linoleic Acid Linolenic Acid Arachidonic acid

Sphingolipids do not have a glycerol backbone; they are formed from ______________

Sphingosine

What is sphingosine derived from?

Serine and palmitate (a specific fatty acid)

Ceramides are _____________ formed from sphingosine by attaching a fatty acid to the amino group

Amides

Sphingolipids are formed by attaching different groups to the _____________ on ceramide

Hydroxyl group

What are the properties of the lipoprotein 'Chylomicron'?

- Largest - Lowest in density due to high lipid to protein ratio - Highest in triacylglycerols as % of weight

What is the property of VLDL (very low density lipoprotein)?

2nd highest in triacyglycerols as % of weight

What does IDL stand for?

Intermediate Density Lipoprotein

What is the property of LDL (Low density lipoprotein)?

Highest in cholesteryl esters as % of weight

HDL (high density lipoprotein) is highest in _________ due to high protein/lipid ratio

Density

What are 'derived lipids'?

A large variety of highly lipid-like compounds or compounds derived from the intermediates of lipid metabolism

What can derived lipids be classified into?

Terpenes (Isoprenoids) & Eicosanoids

What are the chemical properties of Isoprene?

- A five carbon compound derived from condensation of acetyl co-enzyme A molecule - Can be linked in terpenes to form a variety of straight chain or cyclic molecules

What are some examples of terpenes?

Steroids Sterols Fat soluble vitamins Bile salts Pigment

What are the properties of Steroids?

- Not formed from fatty acids but have some lipid like characters - Posses 17 carbon nucleus of four fused hydrocarbon rings - Steroids differ in the number and position of double bonds between carbon atoms and in the side group linked to the ring

What are some examples of steroids?

Cholesterol Ergosterol Bile Salts Sex hormones Pigments

___________ is the steroid precursor in human cells from which all of the steroid hormones are synthesised by modifications to the ring or C-20 side chain

Cholesterol

___________ is a steroid and a hormone secreted by the adrenal gland

Cortisol

____________ is a steroid and is a male sex hormone

Testosterone

Cholesterol is not very water soluble so it is converted to amphipathic water-soluble bile salts such as ____________________

Cholic acid

What is the purpose of bile salts?

Bile salts line the surfaces of lipid droplets (micelles) in the lumen of the intestine where they keep the droplets emulsified in the aqueous environment

Eicosanoids are compounds derived from polyunsaturated fats, give three examples:

Prostaglandins Thromboxanes Leucotrienes

What are the properties of Prostaglandins?

Prostaglandins are hormone-like compounds that are hydroxy derivatives of 20 carbon polyunsaturated fatty acids

Where can prostaglandins be found and what are their functions?

Prostaglandins can be found in human seminal fluid, uterus, stomach and lungs. Functions include inflammation, allergic reaction, blood clotting and smooth muscle contraction

Where are Thromboxanes formed and what is its function?

Thromboxanes are formed in the blood platelets and are associated with blood clotting

___________ are secreted by leucocytes and include contraction of muscle in the lining of air passages to the lungs

Leucotrienes (Overproduction of leukotrienes causes asthmatic attacks)

What is the structure of an amino acid?

Amino acids contain an amino group, carboxyl group, H atom and an 'R' (side chain) group surrounding a central carbon atom